Welcome to Earth

Describe features of the Earth that distinguish it from other planets, including its water surface and atmosphere

70% of the surface of the crust consists of water in the form of the seas, oceans and lakes. The oceans regulate the Earth’s temperature, storing and releasing heat from the Sun. 30% is land mass made up of continents and islands.

Earth is unique in having liquid water on its surface, yet water is surprisingly common in the Solar System. We can see some evidence of it existing on Mars, and can detect it as water vapour or ice in moons, planet atmospheres or comets. The Moon has some ice in deep craters near the poles.

We would like to believe there are other life forms in the Solar System, but without evidence of liquid water, it is difficult to prove. Water is the basic necessary molecule for life to exist, which is why water is something that really excites astronomers.

Our atmosphere supports life. We breathe in Oxygen and breathe out Carbon Dioxide (which is what plants breathe in, then they breath out Oxygen). If there was one attribute that makes Earth unique in our Solar System it is that it supports life.

Other reasons why life exists are that:

  • We have a magnetic field which deflects solar particles from the Sun.
  • Our atmosphere also absorbs harmful rays from space.
  • Our planet is positioned in a habitable zone, where water can exist as a liquid to support life. This is a region far enough from the Sun to stay warm, but not near enough to evaporate.



List and comment on at least 3 things that make Earth different from other planets.